1. Technical Field of the Invention
This invention relates to liquid amine terminated derivatives of diglycidyl ethers. More particularly, this invention relates to liquid amine terminated derivatives of diglycidyl ethers prepared from diglycidyl ethers of Bisphenol A and polyoxyalkylene diamines, as hereinafter defined. Still more particularly, this invention relates to liquid amine terminated derivatives of diglycidyl ethers prepared by reacting polyoxyethylene diamines with the epoxy terminated derivatives of glycidyl ethers of Bisphenol A and polyoxyalkylene diamines.
In another aspect, this invention relates to a method for preparing epoxy terminated derivatives of diglycidyl ethers. In yet another aspect, the present invention relates to a method of preparing amine terminated derivatives of diglycidyl ethers by reacting polyoxyethylene diamines with epoxy terminated amine derivatives of diglycidyl ethers of Bisphenol A and polyoxyalkylene diamines.
Both the epoxy terminated derivatives of the present invention and the amine terminated derivatives of the present invention are useful in the preparation of epoxy resins.
The epoxy terminated derivatives of diglycidyl ethers of Bisphenol A may be characterized as follows: ##STR1## wherein:
R represents a polyoxyalkylene group having the formula: ##STR2##
R" represents hydrogen, methyl or ethyl,
n is a positive number having a value of about 2 to about 35,
R' represents a glycidyl ether having the formula: ##STR3##
wherein n' represents 0 or a positive number having a value of 1 or 2.
The amine terminated derivatives of diglycidyl ethers of Bisphenol of the present invention may be characterized as amine terminated derivatives having the formula: ##STR4##
wherein d is a positive number having an average value of 1 to about 4, and
wherein X represents a group having the formula: ##STR5##
wherein:
R represents a polyoxyalkylene group having the formula: ##STR6##
R" represents hydrogen, methyl or ethyl,
n is a positive number having a value of about 2 to about 35,
R' represents a glycidyl ether having the formula: ##STR7##
wherein n' represents 0 or a positive number having a value of 1 or 2.
Both the epoxy terminated derivatives and the amine terminated derivatives of the present invention, although with comparatively high molecular weights in the order of from about 2000 to about 10,000, are liquids at ambient temperatures. This is surprising, because the normally expected products from such reactants would be gels. Polyether amines are standard reaqents for the curing of epoxy resins to solid products.
It has been discovered in accordance with the present invention that liquid epoxy terminated derivatives and liquid amine terminated derivatives having the formulas set forth above can be prepared by following the method of the present invention.
In accordance with the method of the present invention wherein epoxy terminated derivatives are to be prepared, a diglycidyl ether is dissolved in acetone and/or methylethyl ketone to prepare a charge solution which is mixed with from about 4 to 5 moles of a polyoxyalkylene diamine per mole of the diglycidyl ether to provide an initial reaction mixture and the initial reaction mixture is heated at a temperature of about 80.degree. to about 160.degree. C. for about 1 to 4 hours sufficient to permit the diglycidyl ether to quantitatively react with the polyoxyalkylene diamine and substantially completely volatilize the solvent to thereby form an epoxy terminated derivative of the diglycidyl ether.
In accordance with another embodiment of the present invention, the thus-formed reaction mixture containing the epoxy terminated derivatives of the diglycidyl ether is mixed with about 4 moles or more (e.g., 4 to 10 moles) of a polyoxyethylene diamine per mole of polyoxyalkylene diamine used in preparing the initial epoxy terminated reaction product.
2. Prior Art
It is well known that various polyamine compounds are widely used as raw materials for hardening agents of epoxy resins. For these resins, typical examples of useful polyamine compounds are aliphatic amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, etc.; aromatic amines such as phenylenediamine, diaminophenylmethane, diaminophenylsulfone, etc.; aliphatic amines having aromatic ring, such as xylylenediamine, etc.; and alicyclic amines such as bisaminomethylcyclohexane, isophoronediamine, etc. These polyamine compounds each has a reactivity of the amino group as the specific feature caused by the active hydrogen and they are used for various purposes. Further, polyamine compounds which have been modified in a manner suitable for the specific polyamine compound have found a variety of uses and the modified compounds are used as hardening agents for epoxy resins.
Adducts from amines and diepoxides have long been used in industry as curing agents for epoxy resins.
It is known from U.S. Pat. No. 3,538,184 (November 1970) that a polyglycidyl ether can be reacted with a hexamethylenediamine to form solvent free liquid adducts of polyepoxides and polyamines which are suitable for use as curing agents for epoxy resins.
In U.S. Pat. No. 3,629,181 there is described a curing agent which comprises the adduct from a polyglycidyl ether of a polyphenyl and a cycloaliphatic or cycloaliphaticaliphatic di-primary diamine, in which at least one of the primary amino groups is bonded to an endocyclic carbon atom of a cycloaliphatic ring.
In U.S. Pat. No. 3,996,175 there are described moulding materials from epoxide resins based on Bisphenol A or on other bis- or polyphenols and epichlorohydrin which contain aromatic amines as curing agents.
U.S. Pat. No. 4,348,505 discloses the preparation of amine adduct curing agents utilizing epoxides of a functionality greater than two which dramatically enhance the chemical resistance properties of the cured epoxy products over results obtained from either free amines or the conventional amine adducts.
In U.S. Pat. No. 4,540,750 it was disclosed that the preparation of diethyl toluene diamine adduct curing agents with epoxides of a functionality of at least two enhances the performance characteristics of cured epoxy and urethane products.
U.S. Pat. No. 4,578,412 is directed to modified (i.e., extended) amine curing agents which are prepared by dissolving a solid elastomeric polyurethane such as RIM polyurethane in an amine of the type used for curing epoxy resins.
A novel polyamine compound made by reacting m-xylyene diamine and epichlorohydrin in the presence of an alkali which is useful as a hardening agent for epoxy resins is disclosed in U.S. Pat. No. 4,605,765.
There are described in U.S. Pat. No. 4,608,404 compositions which contain specific groups of oligomeric diamine hardeners and epoxy compounds which when combined with structural fibers produce composites which have improved tensile properties, high compressive strengths and improved impact resistance and, in addition, demonstrate low moisture absorption.
In an article titled "High Solids Epoxy/Polyamide Coatings", V. Brytus discusses a new polyamide hardener which overcomes the compatibility problem brought about by reducing the molecular weight of epoxy/polyamidoamine maintenance coatings in an attempt to lower the volatile organic content. See Journal of Coatings Technology, Vol. 58, No. 740, September 1986. The polyamide has controlled levels of imidazoline and other constituents having an affinity for the Bisphenol A moiety. A two-step method of producing N,N'-dimethyl diamine compounds for use as epoxide polyaddition compounds is described in U.S. Pat. No. 4,623,746. The resins formed using this compound as a curative can be produced with improved strength, toughness and hot/wet properties.
Wang et al. disclose in U.S. Pat. No. 4,636,535 curable compositions comprising epoxide prepolymers and polyamidobenzoates, alone or combined with reinforcements such as graphite fibers.
In U.S. Pat. No. 4,680,341 epoxy resin systems are disclosed which exhibit good tensile properties and good moisture sensitivity which are made by copolymerizing tetraglycidates with a polyamine curing agent.
From the preceding discussion it is apparent that compositions with a variety of properties which are the product of a wide range of amine and epoxide components are useful in the field of epoxy curing resins.